I definitely agree that the set, state of mind does play an enormous and important role. Unfortunately I wasn't very lucky and ended up in terrible nightmares. If I was thinking of ending my life I would not have known what was real and what wasn't. Besides it's endless. I remember being convinced I would never go back to "normal". Anyway, I believe I understand what you meant. It could work, after all it's an extreme decision and everything should be tried to prevent it.
May I ask, which dissociative it was, that you took in a miserable state of mind ? I still think, that you misunderstood my post and assume, that I try to recommend @Edaw'Naflagn a psychedelic trip to solve all of his problems. I'm sorry if I'm repeating myself here and you already got, that I am talking about taking a (semi-) hole inducing NMDA-antagonist in order to detach the ego from the given data set, that we call past/memory/character and gain a new perspective to ones own life, realize new ways of improving certain expects and integrate those realizations into everyday life.
Yes, all this is theoretically possible during a classical psychedelic trip but in my opinion psychedelics (5ht2a-agonists) tend to overwhelm the mind and can probably cause long lasting after effects and negative thought patterns, because they confront the user with all kinds of potentially negative memories and emotions, that they suppressed. whereas dissociatives bear less dangers in that regard. If the disso-dose is too high, it can of course get too "underwhelming", meaning, that a total detachment from the body and ego is reached (holing), so that usually no revealations come out of disso trips (it is rather a restart), but instead a restart of the mind is achieved, because the ego is dissolved during the peak of the trip and later during the comedown and the following days slowly forming itself back from the available data in the head and environment.
Disso trips are much more recommended for severly depressed people IMHO. When I was depressed and took psychedelics (substances like shrooms, LSD, 2c-x), it always ended in a disaster or a meh experience at best. With dissos (substances like Ketamine, DXM, MXE, 2-Oxo-PCE) you feel like a certain part of you is reborn and you have gotten a chance to readjust that part of you, in order to harmonize better with your environment and fellow humans. But you need a good trip sitter, because during holing you loose control of your body (breathing works find though), but you are usually very calm.
Long post : TLDR? I did NOT talk about about psychedelics, but about dissociatives (pretty good ones are discussed right now in the psychedelics forum, yes they are discussed in the psych forum, but they are a totally other substance class).